In general, a power converter includes a smoothing capacitor module that receives DC power from a DC power source, an inverter circuit configured to generate AC power upon reception of the DC power from the capacitor module, and a control circuit configured to control the inverter circuit.
The AC power obtained by the power converter is supplied to an electric motor (for example, a three-phase synchronous electric motor) and, depending on the supplied AC power, the electric motor generates a rotational torque. The electric motor generally has a function as a power generator, and generates AC power by a rotational force supplied to the electric motor from the outside.
In this manner, the power converter also has a function to convert AC power to DC power in many cases, and AC power generated by the electric motor is converted into DC power. Conversion from DC power to AC power, or conversion from AC power to DC power is controlled by the control apparatus.
For example, when the electric motor is a synchronous electric motor, control relating to the conversion of the power can be performed by controlling a phase of a rotating field that a stator generates with respect to the position of a magnetic pole of a rotor of the synchronous electric motor. An example of the power converter is disclosed in JP-A-2011-217548 (PTL 1).
The power converter is mounted on, for example, a hybrid system automotive vehicle, and generates AC power for supplying to the electric motor which generates a traveling rotational torque upon reception of DC power from a secondary battery mounted on the automotive vehicle. At the time of a regenerative braking operation such as a decelerating operation of the automotive vehicle, the electric motor generates AC power by being rotated by a rotation of wheels for generating a braking force, the generated AC power is converted into the DC power by the power converter, is stored in the secondary battery, and is used as a power for traveling again.